Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients receiving lithium for the management of manic depressive disorders appear to be at increased risk for development of hypercalcemia. Some (but not all) clinical studies and several in vitro studies suggest that lithium alters release of parathyroid hormone. Because hypercalcemia may result from an increase in the mass of parathyroid tissue, we studied the in vitro effect of lithium on tritiated thymidine (3H-TdR) incorporation as a measure of DNA synthesis. Dispersed cells from previously cryopreserved tissue from 18 patients undergoing surgery for single-gland hyperparathyroidism (adenoma) and five patients with secondary hyperparathyroidism were incubated with graded concentrations of lithium chloride and, after a 5-day incubation, were pulsed with 3H-TdR. Adenoma cells exposed to 2.0 mmol/L lithium (therapeutic level is approximately 0.8 to 2.0 mmol/L) demonstrated increased 3H-TdR incorporation compared with cells not exposed to lithium (average increase 56%). Secondary hyperplasia cells exhibited a similar but less striking response. There was no lithium-induced 3H-TdR incorporation in four preparations with normal bovine parathyroid cells. We conclude that lithium in therapeutic doses increases 3H-TdR incorporation into adenoma cells, may serve as a mitogen for human parathyroid adenoma, and could promote or accelerate hyperparathyroidism.
Surgery 1991 Dec
PMID:Lithium increases tritiated thymidine uptake by abnormal human parathyroid tissue. 166 Jun 26

Parathyroid hormone (PTH) and PTH-related protein (PTHrP) act via PTH receptors in bone to stimulate bone resorption. Bone resorption is also stimulated by certain cytokines, which are produced in bone and bone marrow. The effects of such cytokines on the PTH-receptor system were studied in the osteoblast-like osteosarcoma cell line UMR 106-06. 125I-labelled PTHrP-(1-84)-peptide bound specifically to the cells, and PTHrP-(1-34) and -(1-84) competed with equimolar affinity for binding to UMR 106-06 cells. The specific binding of 125I-PTHrP-(1-84) could be completely blocked by PTH. Therefore 125I-PTHrP-(1-84) bound to a classical receptor in UMR 106-06 cells. Preincubation for 3 days with either tumour necrosis factor alpha (TNF alpha) or retinoic acid (RA) both decreased the specific binding of 125I-PTHrP-(1-84) to about 40% of control levels. These effects were specific for PTH binding, since there was little effect on 125I-salmon-calcitonin binding. Both TNF alpha and RA required 24 h exposure to cells to produce a measurable effect. The decrease in 125I-PTHrP-(1-84) binding was due to a reduced number of binding sites, with little apparent change in affinity. Half-maximal effects were seen with 1 ng of TNF alpha/ml, whereas 1 microM-RA was needed to observe the loss of PTH receptors. Combinations of RA and TNF alpha produced a greater effect than that of either agonist alone. The loss of PTH receptors was accompanied by a specific loss of PTH-stimulated cyclic AMP production. Preincubation with TNF alpha increased the basal plasminogen activator (PA) activity in the cells and decreased the amplitude of the response of PA activity to PTH compared with control cells. Furthermore TNF alpha decreased sensitivity to PTH (50% stimulation of PA activity with 0.1 nM-PTH in control cells versus 50% stimulation with 0.3 nM-PTH in TNF alpha-treated cells). In contrast, TNF alpha pretreatment increased the amplitude of the response of PA activity to calcitonin, whereas sensitivity to calcitonin was not altered. These data are consistent with a specific down-regulation of PTH receptors in osteoblast-like UMR 106-06 cells after exposure to TNF alpha or RA. The loss of PTH receptors is accompanied by a decreased responsiveness to PTH, as measured with the PA system in these cells. A loss of PTH receptors could modulate PTH responses in osteoblasts, either in the local control of bone formation and resorption, or in pathological conditions such as humoral hypercalcaemia of malignancy.
Biochem J 1991 Dec 01
PMID:Specific down-regulation of parathyroid hormone (PTH) receptors and responses to PTH by tumour necrosis factor alpha and retinoic acid in UMR 106-06 osteoblast-like osteosarcoma cells. 166 Jul 13

In 1957, Cope and his associates first noted 2 cases of pancreatitis associated with primary hyperparathyroidism. They emphasized the association of hyperparathyroidism and pancreatitis. Since then pancreatitis has become a diagnostic clue to primary hyperparathyroidism. We report herein a 39-year-old woman who had suffered from acute relapsing pancreatitis 3 times in the past 2 years. Hypercalcemia persisted throughout the course. A movable mass 3 x 3 cm in diameter was noted over the right thyroid area on physical examination. A hypoechogenic mass 3.5 x 2.7 x 1.4 cm was found between the right lobe of the thyroid and the carotid artery. Because of a persistently high serum level of Ca2+, normal saline and furosemide were infused; the serum Ca2+ decreased gradually. After aspiration of the suspected mass, the serum level of Ca2+ increased from 8.7 mg/dL to 18 mg/dL. Because of the impression of parathyroid adenoma, surgery was performed and a 3 x 2.5 x 1.5 cm well-encapsulated mass was excised without difficulty. Pathologic examination revealed a well-encapsulated parathyroid adenoma. This case reveals that primary hyperparathyroidism maybe one of the causes of pancreatitis, and aspiration cytology, although it may be helpful for the diagnosis, can aggravate the hypercalcemia.
J Formos Med Assoc 1991 Dec
PMID:Acute relapsing pancreatitis in primary hyperparathyroidism with hypercalcemia aggravated after aspiration cytology: report of a case. 168 89

The geminal bisphosphonates are a new class of drugs characterised by a P-C-P bond. Consequently, they are analogues of pyrophosphate, but are resistant to chemical and enzymatic hydrolysis. The bisphosphonates bind strongly to hydroxyapatite crystals and inhibit their formation and dissolution. This physicochemical effect leads in vivo to the prevention of soft tissue calcification and, in some instances, inhibition of normal calcification. The main effect is to inhibit bone resorption, but in contrast to the effect on mineralisation, the mechanism involved is cellular. These various effects vary greatly according to the structure of the individual bisphosphonate. The half-life of circulating bisphosphonates is very brief, in the order of minutes to hours. 20% to 50% of a given dose is taken up by the skeleton, the rest being excreted in the urine. The half-life in bone is far longer and depends upon the turnover rate of the skeleton itself. Bisphosphonates are very well tolerated; the relatively few adverse events that have been associated with their use are specific for each compound. Bisphosphonates have been used to treat various clinical conditions, namely ectopic calcification, ectopic bone formation, Paget's disease, osteoporosis and increased osteolysis of malignant origin. The three compounds commercially available for use in tumour-induced bone disease are in order of increasing potency, etidronate, clodronate and pamidronate. Most data have been obtained with the latter two agents. By inhibiting bone resorption, they correct hypercalcaemia and hypercalciuria, reduce pain, the occurrence of fractures, as well as the development of new osteolytic lesions, and in consequence improve the quality of life. In view of these actions, of their excellent tolerability and of the fact that they are active for relatively long periods, these compounds are, after rehydration, the drugs of choice in tumour-induced bone disease and an excellent auxiliary to the drugs used in oncology.
Drugs 1991 Dec
PMID:Bisphosphonates. Pharmacology and use in the treatment of tumour-induced hypercalcaemic and metastatic bone disease. 172 40

Using a human keratinocyte model of tumor progression, we have examined the regulation of gene expression and secretion of a parathyroid hormone-like peptide (PLP) that has been implicated in the pathogenesis of hypercalcemia in cancer. A rapid and transient induction of PLP mRNA in response to serum stimulation was demonstrated in both established (HPK1A) and malignant (HPK1A-ras) cells; however the dose dependent increases were greater in HPK1A than in HPK1A-ras. Significant inhibition of this induction was noted with the addition of 1,25-dihydroxyvitamin D3 at a lower concentration in HPK1A than in HPK1A-ras. Amino-terminal PLP immunoreactivity and bioactivity correlated well (r = 0.98) when measured in conditioned medium. In the absence of mitogenic stimuli, malignant keratinocytes (HPK1A-ras) secreted significantly more PLP than established (HPK1A) keratinocytes. However, in response to increasing concentrations of epidermal growth factor and fetal bovine serum, PLP release was far greater from HPK1A (maximum 13 x basal) than from HPK1A-ras (maximum 3 x basal) cells. In addition, 1,25-dihydroxyvitamin D3 was more effective in inhibiting both basal and stimulated PLP secretion in HPK1A than in HPK1A-ras cultures. Reduction of extracellular Ca2+ from 2.0 mM to 0.5 mM appeared to be more effective at an early time point in reducing PLP secretion from the established cells compared with the malignant cells. These studies therefore demonstrate a progressive dysregulation of PLP expression and secretion in human keratinocytes in the transformation from established to malignant phenotype and may have important implications for understanding the pathogenetic mechanisms involved in vivo in the development of hypercalcemia in cancer.
Cancer Res 1991 Dec 15
PMID:Dysregulation of parathyroid hormone-like peptide expression and secretion in a keratinocyte model of tumor progression. 174 25

Historically, primary hyperparathyroidism during pregnancy was associated with significant risk of maternal morbidity and fetal death. Maternal hypercalcemia results in fetal hypercalcemia, leading to suppression of fetal parathyroid gland function. Neonatal hypocalcemia with tetany is a common occurrence after birth when maternal calcium flow is interrupted. From 1930 to 1990, 109 cases of women with primary hyperparathyroidism associated with pregnancy have been reported, 39 of whom were treated surgically before delivery. Although fetal mortality rates for medically treated women have improved, fetal morbidity continues to remain higher than in women who undergo surgical treatment of parathyroid disease during pregnancy. Of 850 patients treated surgically for primary hyperparathyroidism since 1960, 12 were pregnant. Four of the patients were treated medically during pregnancy and underwent surgery after delivery; all four infants had neonatal hypocalcemia and tetany. The remaining eight patients were treated surgically during pregnancy: six in the second trimester and two (one with associated pancreatitis and one with hypercalcemic crisis) during the first trimester. There was no fetal or maternal morbidity or death in the surgical group. Parathyroid adenomas were present in 10 of the patients, hyperplasia in one, and parathyroid carcinoma in one. The management of maternal primary hyperparathyroidism diagnosed during pregnancy should be based on the patient's symptoms and severity of disease. Hyperparathyroidism characterized by progressive symptoms should be treated surgically, preferably during the second trimester. Symptom-free patients and those with mild hypercalcemia diagnosed in the third trimester may be managed medically, postponing operation until after delivery.
Surgery 1991 Dec
PMID:Primary hyperparathyroidism during pregnancy. 174 71

Calcium metabolism and hormonal control after parathyroid adenomectomy are poorly understood. During the first postoperative hours, biologically active intact parathyroid hormone (PTH) (hPTH 1-84) levels are subnormal and, in spite of down-regulation of PTH peripheral receptors (caused by hypercalcemia before surgery), total and ionized calcium concentrations are maintained in the normal range. Serum samples from 20 patients with primary hyperparathyroidism were collected in the immediate preoperative period and 4 and 48 hours after excision of one parathyroid adenoma. Total and ionized calcium, intact (iPTH), midregion (mrPTH) specific PTH (hPTH 53-68), and N-terminal PTH (N-PTH) serum concentrations were determined. Levels of N-PTH were obtained with a radioimmunoassay by a modified reverse immunoextraction procedure that measures N-PTH fragments after exclusion of the interfering iPTH. No significant correlation was found between ionized and total calcium, mrPTH, and iPTH. However, total and ionized calcium levels correlated well with N-PTH (r = 0.9999, p = 0.0054, and r = 0.9993, and p = 0.0226, respectively). The data suggest that the relatively moderate decrease in calcium levels, in spite of marked decrease in circulating iPTH during the first postoperative hours, may be attributable to the minimal decrease of the bioactive N-PTH epitope concentrations. We would hypothesize that hPTH (1-34) fragments may play a significant role in regulating serum calcium levels in the early postoperative period.
Surgery 1991 Dec
PMID:The role of circulating N-terminal parathyroid hormone fragments in the early postparathyroid adenomectomy period. 174 74

It is not clear whether hypercalcemia and hyperparathyroidism associated with lithium therapy are the result of an unmasking of preexisting disease or a direct effect of lithium on the parathyroid glands. To investigate this phenomenon, parathyroid hormone (PTH) secretion and cytosolic calcium concentrations [( Ca]i) were measured in normal and lithium-treated dispersed bovine parathyroid cells grown in tissue culture and incubated with varying concentrations of extracellular calcium [( Ca]e) (0.5 to 2.5 mmol/L). Results indicate that lithium has two effects on parathyroid secretory response: (1) a decrease in low calcium-stimulated PTH release and (2) a potentiation of PTH release at physiologic concentrations of extracellular calcium. [Ca]i was assessed by use of fura-2, a calcium-sensitive fluorescent indicator. Resting [Ca]i levels were unaffected by lithium (103 +/- 13 nmol/L in controls vs 101 +/- 5 nmol/l in lithium-treated cells, mean +/- SE). Subsequent increases in [Ca]i in response to increases in [Ca]e were significantly less in lithium-treated cells, with no difference at maximal [Ca]e. Increases in [Ca]i in response to a submaximal concentration of extracellular magnesium were also blunted in cells pretreated with lithium. In conclusion, our data suggest that, at physiologic calcium concentrations, lithium decreases parathyroid cell sensitivity to changes in [Ca]e, reducing [Ca]i levels and increasing PTH secretory response.
Surgery 1991 Dec
PMID:Lithium effects on dispersed bovine parathyroid cells grown in tissue culture. 174 76

The incidence of parathyroid carcinoma in patients surgically treated for primary hyperparathyroidism at the University of Michigan Hospital was 0.4% during an 18-year period. The courses of the five patients with metastatic disease are described. Histologic reevaluation and assessment of the DNA ploidy pattern were performed in each case. Localization studies preceded all reexplorations. The number of operative procedures in each patient ranged from two to 10. Two patients are living with recurrent disease and one has been disease free for 42 months. Two patients died after 2 and 12 years, respectively. Three patients had aneuploid tumors; one had a diploid tumor. One patient had both aneuploid and diploid cell populations. Dilemmas in diagnosis, localization, and medical and surgical management were encountered in patients with metastatic carcinoma. The chosen treatment should be evaluated individually in each case because of the variability in aggressiveness of this malignancy. Surgical resection proved most effective in some of these patients for both local and distant recurrences. Bisphosphonates and gallium nitrate have been reported to be effective in controlling hypercalcemia. Only the former had some effect in one of our patients.
Surgery 1991 Dec
PMID:Metastatic parathyroid carcinoma: dilemmas in management. 174 86

Parathyroid hormone-related protein (PTHrP), which is responsible for producing hypercalcemia in patients with humoral hypercalcemia of malignancy, has recently been identified in several normal tissues. Because PTHrP, like parathyroid hormone (PTH), is known to exhibit vasodilatory properties, we investigated the expression and regulation of PTHrP mRNA in cultured rat aortic smooth muscle cells (SMC). We report here that PTHrP mRNA is expressed in SMC and is markedly induced by serum in a time- and concentration-dependent fashion. Addition of 10% fetal calf serum to serum-deprived, confluent cells, resulted in a marked induction of PTHrP mRNA by 2 h with a peak at 4-6 h. PTHrP was detected in SMC by immunocytochemistry and radioimmunoassay of conditioned medium, and was shown to be up-regulated within 24 h after the addition of serum. The serum induction of PTHrP mRNA was blocked by actinomycin D and by cycloheximide indicating the need for protein synthesis to evoke the serum effect on PTHrP gene transcription. In addition, treatment with dexamethasone, which has been previously shown to reduce the constitutive expression of PTHrP in human cancer cells, also blunted the serum induction of PTHrP mRNA in SMC. Treatment of quiescent cells with the serum mitogens platelet-derived growth factor or insulin-like growth factor-I had no effect on PTHrP, whereas the vasoactive peptides endothelin, norepinephrine and thrombin stimulated PTHrP expression. Exogenous addition of recombinant PTHrP-(1-141) had no significant effect on SMC DNA synthesis as measured by [3H]thymidine incorporation. In summary, the abundance of PTHrP mRNA and the characteristics of its regulation in SMC suggest a major role for PTHrP as a local modulator in vascular smooth muscle.
J Clin Invest 1991 Dec
PMID:Abundant expression of parathyroid hormone-related protein in primary rat aortic smooth muscle cells accompanies serum-induced proliferation. 175 45


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